trouble with tip show on tree node/leaf

trouble with tip show on tree node/leaf :
use the following at tree static leaf creation for tip.
...
text: 'my leaf',
qtip: 'long text description up to a hundred words',
...
but unfortunately it is not easy to get tip shown while moving mouse
over the tree leaf text title 'my leaf', it seems the tip shows only
when mouse is positioining at the right bottom of the tree leaf tittle
'my leaf'.

how can I make qtip show when mouse is over or hover of the tree leaf
title ?